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116
The statistical determinants of adaptation rate in human reaching
- J Vis
, 2008
"... Rapid reaching to a target is generally accurate but also contains random and systematic error. Random errors result from noise in visual measurement, motor planning, and reach execution. Systematic error results from systematic changes in the mapping between the visual estimate of target location a ..."
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Cited by 38 (6 self)
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Rapid reaching to a target is generally accurate but also contains random and systematic error. Random errors result from noise in visual measurement, motor planning, and reach execution. Systematic error results from systematic changes in the mapping between the visual estimate of target location and the motor command necessary to reach the target (e.g., new spectacles, muscular fatigue). Humans maintain accurate reaching by recalibrating the visuomotor system, but no widely accepted computational model of the process exists. Given certain boundary conditions, a statistically optimal solution is a Kalman filter. We compared human to Kalman filter behavior to determine how humans take into account the statistical properties of errors and the reliability with which those errors can be measured. For most conditions, human and Kalman filter behavior was similar: Increasing measurement uncertainty caused similar decreases in recalibration rate; directionally asymmetric uncertainty caused different rates in different directions; more variation in systematic error increased recalibration rate. However, behavior differed in one respect: Inserting random error by perturbing feedback position causes slower adaptation in Kalman filters but had no effect in humans. This difference may be due to how biological systems remain responsive to changes in environmental statistics. We discuss the implications of this work.
Attention alters the appearance of motion coherence
- Psychonomic Bulletin & Review
, 2006
"... Selective attention enhances visual information processing, as measured by behavioral performance and neural activity. However, little is known about its effects on subjective experience. Here, we investigated the effect of transient (exogenous) attention on the appearance of visual motion, using a ..."
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Cited by 22 (14 self)
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Selective attention enhances visual information processing, as measured by behavioral performance and neural activity. However, little is known about its effects on subjective experience. Here, we investigated the effect of transient (exogenous) attention on the appearance of visual motion, using a psychophysical procedure that directly measures appearance and controls for response bias. Observers viewed pairs of moving dot patterns and reported the motion direction of the more coherent pattern. Directing attention (via a peripheral precue) to a stimulus location increased its perceived coherence level and improved performance on a direction discrimination task. In a control experiment, we ruled out response bias by lengthening the time interval between the cue and the stimuli, so that the effect of transient attention could no longer be exerted. Our results are consistent with those of neurophysiological studies showing that attention modulates motion processing and provide evidence of a subjective perceptual correlate of attention, with a concomitant effect on performance. Attention is the mechanism that allows us to selectively process the vast amount of information that we receive and to guide our behavior. Visual spatial attention can be deployed overtly, accompanied by eye movements
Averaging facial expression over time
- J. Vis
, 2009
"... The visual system groups similar features, objects, and motion (e.g., Gestalt grouping). Recent work suggests that the computation underlying perceptual grouping may be one of summary statistical representation. Summary representation occurs for low-level features, such as size, motion, and positio ..."
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Cited by 19 (5 self)
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The visual system groups similar features, objects, and motion (e.g., Gestalt grouping). Recent work suggests that the computation underlying perceptual grouping may be one of summary statistical representation. Summary representation occurs for low-level features, such as size, motion, and position, and even for high level stimuli, including faces; for example, observers accurately perceive the average expression in a group of faces (J.
First evaluation of a novel tactile display exerting shear force via lateral displacement
- ACM Trans. on Applied Perception
, 2000
"... Based on existing knowledge on human tactile movement perception, we constructed a prototype of a novel tactile multipin display that controls lateral pin displacement and, thus produces shear force. Two experiments focus on the question of whether the prototype display generates tactile stimulation ..."
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Cited by 14 (3 self)
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Based on existing knowledge on human tactile movement perception, we constructed a prototype of a novel tactile multipin display that controls lateral pin displacement and, thus produces shear force. Two experiments focus on the question of whether the prototype display generates tactile stimulation that is appropriate for the sensitivity of human tactile perception. In particular, Experiment I studied human resolution for distinguishing between different directions of pin displacement and Experiment II explored the perceptual integration of information resulting from the displacement of multiple pins. Both ex-periments demonstrated that humans can discriminate between directions of the displacements, and also that the technically realized resolution of the display exceeds the perceptual resolution (>14◦). Experiment II demonstrated that the human brain does not process stimulation from the different pins of the display independent of one another at least concerning direction. The acquired psychophysical knowledge based on this new technology will in return be used to improve the design of the display.
Distortion in 3d shape estimation with changes in illumination
- Proceedings of the 4th symposium on Applied perception in graphics and visualization
, 2007
"... Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of ..."
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Cited by 13 (0 self)
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Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or a fee. Request
Texture and haptic cues in slant discrimination: reliability-based cue weighting without statistically optimal cue combination
- J. OPT. SOC. AM. A
, 2005
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Evaluating comparative and equality judgments in contrast perception: Attention alters appearance
"... Covert attention not only improves performance in many visual tasks but also modulates the appearance of several visual features. Studies on attention and appearance have assessed subjective appearance using a task contingent upon a comparative judgment (e.g., M. Carrasco, S. Ling, & S. Read, 2 ..."
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Cited by 11 (4 self)
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Covert attention not only improves performance in many visual tasks but also modulates the appearance of several visual features. Studies on attention and appearance have assessed subjective appearance using a task contingent upon a comparative judgment (e.g., M. Carrasco, S. Ling, & S. Read, 2004). Recently, K. A. Schneider and M. Komlos (2008) questioned the validity of those results because they did not find a significant effect of attention on contrast appearance using an equality task. They claim that such equality judgments are bias-free whereas comparative judgments are biasprone and propose an alternative interpretation of the previous findings based on a decision bias. However, to date there is no empirical support for the superiority of the equality procedure. Here, we compare biases and sensitivity to shifts in perceived contrast of both paradigms. We measured contrast appearance using both a comparative and an equality judgment. Observers judged the contrasts of two simultaneously presented stimuli, while either the contrast of one stimulus was physically incremented (Experiments 1 and 2) or exogenous attention was drawn to it (Experiments 3 and 4). We demonstrate several methodological limitations of the equality paradigm. Nevertheless, both paradigms capture shifts in PSE due to physical and perceived changes in contrast and show that attention enhances apparent contrast.
Do common mechanisms of adaptation mediate color discrimination and appearance? Uniform backgrounds
- JOSA A
, 2005
"... Color vision is useful for detecting surface boundaries and identifying objects. Are the signals used to perform these two functions processed by common mechanisms, or has the visual system optimized its processing separately for each task? We measured the effect of mean chromaticity and luminance o ..."
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Cited by 11 (5 self)
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Color vision is useful for detecting surface boundaries and identifying objects. Are the signals used to perform these two functions processed by common mechanisms, or has the visual system optimized its processing separately for each task? We measured the effect of mean chromaticity and luminance on color discriminability and on color appearance under well-matched stimulus conditions. In the discrimination experiments, a pedestal spot was presented in one interval and a pedestal + test in a second. Observers indicated which interval contained the test. In the appearance experiments, observers matched the appearance of test spots across a change in background. We analyzed the data using a variant of Fechner's proposal, that the rate of apparent stimulus change is proportional to visual sensitivity. We found that saturating visual response functions together with a model of adaptation that included multiplicative gain control and a subtractive term accounted for data from both tasks. This result suggests that effects of the contexts we studied on color appearance and discriminability are controlled by the same underlying mechanism. 1.
The effects of task and saliency on latencies for colour and motion processing
, 2003
"... INTRODUCTION There has been much recent interest in looking at the time taken to process various visual-stimulus attributes, such as colour, form and motion. It is commonly accepted that different visual attributes are processed relatively independently in separate parts of the brain (Zeki 1978; Li ..."
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Cited by 10 (0 self)
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INTRODUCTION There has been much recent interest in looking at the time taken to process various visual-stimulus attributes, such as colour, form and motion. It is commonly accepted that different visual attributes are processed relatively independently in separate parts of the brain (Zeki 1978; Livingstone & Hubel 1988). These different attributes may have different processing latencies. Nevertheless, we are rarely aware of such asynchronies. How can these observations be reconciled? Does the brain compensate for differences in processing time, such that a unified percept is recovered that mirrors the synchrony of real-world events? Research by Moutoussis & Zeki (1997) suggested that colour reaches our awareness faster than motion. When objects are repeatedly and rapidly changing colour (between red and green) and switching motion direction with the same frequency, then colour changes must occur ca. 80 ms after motion changes for them to be perceived as synchronous. In the framework
